Additive combination for cold flow improvement of distillate fuel oil

ABSTRACT

Additive combinations of (A) alkyl aromatics, e.g., the condensation product of chlorinated wax and naphthalene, with: (B) ethylene-containing polymers, e.g., copolymers of about 4 to 30 molar proportions of ethylene copolymerized with an unsaturated ester, and/or (C) N-aliphatic hydrocarbyl succinamic acids and/or their amine salts, are cold flow improvers for distillate petroleum fuels.

United States Patent 11 1 F eldman 1 ADDITIVE COMBINATION FOR COLD FLOWIMPROVEMENT OF DISTILLATE FUEL OIL [75] Inventor: NicholasFeldman,Woodbridge,

[73] Assignee: Exxon Research and Engineering Company, Linden, NJ.

[22] Filed: Aug. 9, 1974 [21] Appl. No.: 496,004

Related U.S. Application Data [63] Continuation of Ser. No. 283,548,Aug. 24, 1972,

3,444,082 5/1929 Kautsky 44/71 X 3,449,251 6/1969 Tunkel et a1 1. 44/66X 3,475,321 10/1929 Hensclman et a1. 44/62 X 3,544,467 12/1970 Kautsky44/71 X 3,639,226 2/1972 Henselman et a1. 44/62 X FOREIGN PATENTS ORAPPLICATIONS 993,744 6/1965 United Kingdom 44/80 Primary ExaminerDanielE. Wyman Assistant Examiner-Y. Harris-Smith Attorney, Agent, or FirmFrank T. .lohmann; Roland A. Dexter [57] ABSTRACT Additive combinationsof (A) alkyl aromatics, e.g., the condensation product of chlorinatedwax and naphthalene, with: (B) ethylene-containing polymers, e.gcopolymers of about 4 to 30 molar proportions of ethylene copolymerizedwith an unsaturated ester, and/or (C) N-aliphatic hydrocarbyl succinamicacids and/or their amine salts, are cold flow improvers for distillatepetroleum fuels.

11 Claims, No Drawings ADDITIVE COMBINATION FOR COLD FLOW IMPROVEMENT OFDISTILLATE FUEL OIL This is a continuation of application Ser. No.283,548

filed Aug. 24, 1972, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The inventionrelates to a combination of an alkyl aromatic with anethylene-containing.polymer and/or a succinamic acid material forimproving the cold flow properties of distillate fuel oil.

2. Description of the'Prior Art 5 u Kerosene, which is a solvent forwax, has traditionally been a component of distillate fuel oils, e.g.,diesel fuels, home heating oils, etc. With the demands for kerosene foruse in jet fuels, the amount of kerosene used in distillate fuel oilshas decreased over the years. This, in turn, has frequently required theaddition of wax crystal modifiers, e.g., pour point depressantadditives, to the fuel oil to make up the lack of kerosene.

One class of such pour point depressant additives are alkylatedaromatics, particularly the wax-naphthalene pour point depressants.These materials have been used in various petroleum oils, such aslubricating oils, e.g., see U.S. Pat. Nos. 1,815,022 and 2,297,292; asdewaxing aids, including use with otherco-additives, e.g., see US. Pat.Nos. 3,417,010 and 3,475,32l; and as pour depressants for middledistillate fuels, e.g., see US. Pat. No. 3,245,366. 1

, Another class of pour point depressant additives are ethylenecontaining polymers. The more effective of these polymers for distillatefuel oil are copolymers of ethylene with othermonomers, e.g., copolymersof ethylene and vinyl esters of lower fatty acids such as vinyl acetate(U.S. Pat. No. 3,048,479); copolymersof'ethylene and alkyl acrylate(Canadian Pat. No. 676,875); terpolymers of ethylene with vinyl estersand alkyl fumarates (US Pat. No. 3,304,261 and 3,341,309); polymers ofethylene with other lower olefiris; etc. Also, homopolymers of ethylene(British Pat. Nos/848,777 and 993,744) and chlorinated polyethylene(Belgium Pat. No. 707,371 are now known as distillate pour depressants.

Still another class of pour point depressants are N- aliphatichydrocarbyl succinamic acid disubstit uted on the nitrogen, and itsamine salts as taught in U.S. Pat.

Nos. 3,444,082 and 3,544,467.

SUMMARY OF THE INVENTION The present invention is based uponfinding thatcombinations of (A) alkylated aromatics with: (B)

ethylene-containing polymeric pour point depressants fuel oil, sometimesdo not sufficiently reduce the parti- 7 cle size of the wax crystalsthat form. These large wax particles tend to be filtered out bythescreens and.

other filter equipment normally used on tracks and in fuel oil storagesystems, etc., with a resultingplugging of these screens and filterseven though the temperature of the oil is substantially above its pourpoint. In general, the combinations of the invention can control the waxcrystal size more effectively-then either materialalone. v

Because of this increased effectiveness in regulating:

wax crystal size, the additive combination of the-invention isparticularly useful in diesel fuels in view of the- The wax crystalsizeof these fuels will frequently need to be controlled. For example,in the normal operation of diesel trucks, the diesel engine is usuallyprovided with a fine mesh filter of about 50 microns, e.g., aboutequivalent to.a 270 mesh screen, ahead of the engine. In cold weatherwhen the ambient temperature is below the cloud point, it becomesespecially essential that the wax crystals that form are sufficientlyfine so that they will pass through any filters. As'previouslyindicated, the present invention provides an additive combination whichcan be used to reduce or regulate the wax crystal size to thereby obtainimproved cold flow properties.

In general, the compositions of the invention will comprise a majoramount of a distillate fuel oil improved in flow characteristics by aminor, flow improving amount of: (A) an alkyl aromatic with either (B)an' ethylenepolyrneric pour point depressant and/or (C) an N-aliphatichydrocarbyl succinamic acid or-ami'ne salt,' usually in relative ratiosof 0.3 to 10, preferably 0.5 to 5, parts by weight of (A) per part .byweight-.of

(B) and/or (C).

THE DISTILLATE FUELS In general the distillate fuel oils of theinvention will boil in the range of 250 to 900F., and will have cloudpoints usually from about 20F. to about 45F. The fuel oil can comprisestraight run, or cracked gas oil, or a blend in any proportion ofstraight run and thermally and/on catalytically cracked distillates,etc. Themost common petroleummiddle distillate fuels are kerosene,diesel fuels", jet fuels and heating oils. The low temperature flowproblem is most usually encountered with dieselfuels and with heatingoils.

A typical heating oilspecification calls for a lOJpe r cent-distillationpoint no higher than about 440F., a 50 percent point no higher thanabout 520F., and a percent point of at least540F. and no higher thanabout 640F. to 650F., although some specifications set the 90 percentpoint as high as 675F.

A typical specification for a diesel fuel includes a minimum flash pointof F., and a 90 percent distillation point (ASTMD-1l60) between 540F.and 640F., (See ASTM Designations D-496and D-975).

An example of a high cloud diesel fuel is a 40F.

cloud point fuel having an initial boiling point of about I 350F., a 90percent distillation point of about 73F.

and a final boiling point of about 8479F. (ASTM-D- 1160). h

(A') TI-IE ALKY ARoMAlficg These materials are usually madeby theFriedel- Crafts condensation of. a halogenated paraffin or. an olefinwith an aromatic hydrocarbon. They are well known in the art, primarilyas lube oil pour depressants and as dewaxing aids as previouslymentioned. Usually. the halogenated paraffin will contain from about 15to about 60, e.g., 16 to about 50 carbons, and from about to about 25wt. percent, e.g., to 18 wt. percent, chlorine. Typically, thehalogenated paraff'lns are prepared by chlorinating to the above recitedchlorine content a paraffin wax having a melting point within the rangeof about 100 to 200F. The aromatic hydrocarbon used usually contains amaximum of three substituent groups and/or condensed rings. It may be ahydroxy compound such as phenol, cresol, xylenol, or an amine-such asaniline, but is preferably naphthalene, phenanthrene or anthracene.

(B) THE ETHYLENE CONTAlNlNG POUR DEPRESSANT In general, these polymericpour depressants have a polymethylene backbone which is divided intosegments by hydrocarbon or oxy-hydrocarbon side chains. Theseoil-soluble polymers will generally have a number average molecularweight in the range of about 500 to 50,000, preferably about 1,000 toabout 5,000, as measured for example, by Vapor Pressure Osmometer, suchas using a Mechrolab Vapor Pressure Osmometer Model 310A. Generally,they will comprise about 3 to 40, preferably4 to 20, molar proportionsof ethylene per molar proportion of a second ethylenically unsaturatedmonomer, which latter monomer can be a single monomer or a mixture ofsuch monomers in any proportion.

The unsaturated monomers, copolymerizable with ethylene, includeunsaturated mono and diesters of the general formula:

R1 ll wherein R is hydrogen or methyl; R is a OOCR or -COOR,, groupwherein R is hydrogen or a C to C preferably a C to C straight orbranched chain alkyl group; and R is hydrogen or COOR The monomer, whenR and R are hydrogen and R is -OOCR, includes vinyl alcohol esters of Cto C monocarboxylic acids, preferably C to C monocarboxylic acid.Examples of such esters include vinyl acetate, vinyl isobutyrate, vinyllaurate, vinyl myristate, vinyl palmitate, etc. When R is -COOR suchesters include methyl acrylate, isobutyl acrylate, methyl methacrylate,lauryl acrylate, C Oxo alcohol esters of methacrylic acid, etc. Examplesof monomers where R is hydrogen and R and R are COOR groups, includemono and diesters of unsaturated dicarboxylic acids such as: mono C Oxofumarate, di-C Oxo fumarate, di-isopropyl maleate; di-lauryl fumarate;ethylmethyl fumarate; etc.

Another class of monomers that can be copolymerized with ethyleneinclude C to C alpha monoolefins, which can be either branched orunbranched, such as propylene, isobutene, n-octene-l, isooctene-l,ndecene-l, dodecene- 1, etc.

Still other monomers include vinyl chloride, although essentially thesame result can be obtained by polyethylene chlorinated to contain about5 to 35 wt. percent Chlorine. Even branched polyethylene can be used perse as the pour depressant.

These polyethylene and ethylene copolymer pour depressants are generallyformed using a free radical promotor, or in some cases they can beformed by thermal polymerization, or they can be formed by Ziegler typepolymerization in the case of ethylene with other olefms. The polymersproduced by free radical polymerization appear to be the more importantand can be formed as follows: Solvent, and 050 wt. percent, of the totalamount of monomer other than ethylene, e.g., an ester monomer, used inthe batch, are charged to a stainless steel pressure vessel which isequipped with a stirrer and cooling coil. The temperature of thepressure vessel is then brought to the desired reaction temperature,e.g., to 250C., and pressured to the desired pressure with ethylene,e.g. 800 to 10,000 psig., usually 900 to 6,000 psig. Then promoter,usually diluted with the reaction solvent, and additional amounts of thesecond monomer, e.g., unsaturated ester, are added to the vesselcontinuously, or at least intermittently, during the reaction time,which continuous addition gives a more homogeneous copolymer product ascompared to adding all the unsaturated ester at the beginning of thereaction. Also during this reaction time, as ethylene is consumed in thepolymerization reaction, additional ethylene is supplied through apressure controlling regulator so as to maintain the desired reactionpressure fairly constant at all times. Following the completion of thereaction, usually a total reaction time of A to 10 hours will suffice,the liquid products are withdrawn from the pressure vessel, and thesolvent removed by stripping, leaving the polymer as residue.

(C) THE SUCCINAMIC ACID MATERIALS A description of these materials isgiven in US. Pat. Nos. 3,444,082 and 3,544,467, which description is asfollows:

The alkenyl succinamic acids preferably (n-aliphatic hydrocarbyl)succinamic acids will, for the most part, have the following formula:

R-CH-COX -cox wherein R is a straight chain aliphatic hydrocarbon grouphaving from O to 1 site of olefinic unsaturation (alkyl or alkenyl)attached at a secondary carbon atom to the succinyl group and is of atleast 14 carbon atoms, generally in the range of 15 to 40 carbon atomsand more usually in the range of 15 to 30 carbon atoms. One of X and Xis hydroxyl and the other is:

wherein N has its normal meaning of nitrogen and Y and Y are aliphatichydrocarbyl groups of from 14 to 40 carbon atoms, more usually of from15 to 30 carbon atoms, having a total of from about 30 to 52 carbonatoms, more usually of from 32 to 48 carbon atoms, and, preferably, offrom 32 to 40 carbon atoms.

Y and Y can be aliphatically saturated or aliphatically unsaturated,generally free of acetylenic unsaturation (alkyl or alkenyl). There maybe from 1 to 2 sites of olefinic unsaturation. Y and Y may be the sameor different and may be straight chain or branched chain, preferablystraight chain. The branches will normally be not greater than 1 carbonatom, i.e.,"methyl. The po sition of attachment to nitrogen may be at'aterminal or internal carbon atom.

As is evidenced from the above formula, it is not important whichposition the alkyl or alkenyl group has in relation to the carboxamideor carboxyl group. Because of the bulky nature of the amine, the usualmethod of preparation through the succinic anhydride will provide thealkenyl group B to the carboxamide as the major product. Tothe extentthat that this is the more easily accessible derivative, this derivativeis preferred. However, as far as operability is concerned, either isomeror a mixture of the two isomers may be used.

Individual compounds or mixtures of compound may be used. Mixtures ofdifferent C- and/or N-substituents, both as to homologs and isomers,will frequently be employed when the individual precursors to thesuccinamic acid product are not readily available.

Illustrative succinamic acids include N,N- dihexadecylhexadecylsuccinamic acid, N-hexadecyl, N-octadecyl octadecylsuccinamicacid, N-N- dihexadecenyl C, alkenylsuccinamic acid, N- hexadecenylN-eicosc'riyl 'octadecylsuccinamic acid, N,N-dioctadecenyl C-alkenylsuccinamic ac'id, etc.

As indicated previously,'-the succinamic acid may be used as its aminesalt, preferably as a mixture of acid and amine salt.

.The amine salt or the acid or mixtures thereof can be represented bythe following formula:

R pacox CH2-COX3 wherein R is as previously defined, one of the X and Xis l IYY wherein Y and Y have been previously defined. The other of Xand X is of the formula:

wherein Y and Y may be hydrogen, aliphatic hydrocarbon of from 1 to 30carbon atoms or oxaliphatic hydrocarbon (there being 1 ethereal oxygenatom present in the radical bonded to nitrogen at least ,8 to thenitrogen atom) of from 3 to 30 carbon atoms. Y and Y may be takentogether to form a heterocyclic ring of from 5 to 7 members havingnitrogen and oxygen as the only heteromembers, It varies from 0 to 1,preferably from 0.1 to 0.9. That is, from 10 to 90 mole percent of thesuccinamic acid present is in the form of its salt.

The aliphatic hydrocarbon groups are preferably saturated and ifunsaturated usually have no more than 2 sites of ethylenic unsaturation.The total number of carbon atoms for HNY Y will be from 0 to 60, usually1 to 40.

The groups indicated for Y and Y may also be used for Y and Y. However,as already indicated, primary amines may be used as well as secondaryamines to form the salt. Usually, where an amine other than the one usedto prepare the succinamic acid is used to form the salt, as will beexplained subsequently, there will be a mixture of salts; both the addedamine and the secondary amine employed to prepare the succinamic acidwill be involved in salt formation.

Illustrative amines which may be used to form salts are di-sec-butylamine. lwntl amine dot'lccyl amine.

octadecyl amine, tert-butyl amine, morpholine, diethyl amine,methoxybutylamine, methoxyhexylamine, etc.

The alkyl or alkenyl succinamic acids of this invention are readilyprepared by reacting an alkyl or alkenyl succinic anhydride with thedesired secondary amine at a temperature in the range of about to 250F.in approximately equimolar amounts, either neat or in the presence of aninert solvent. The time for the reaction is generally in the range of 15minutes to 1 hour. This reaction is well known in the art and does notrequire extensive discussion here.

The alkyl or alkenyl succinic anhydrides that are used may be individualcompounds or mixtures of compounds. That is, various alkyl or alkenylgroups of differing number of carbon atoms or different positions ofattachment to the succinic anhydride group may be used. Alternatively, asingle isomer may be used. Since mixtures are generally more readilyavailable, to that degree they are preferred. Frequently, mixtures willbe used of aliphatic hydrocarbyl substituted succinic anhydrides whereinno single homolog is present in amount greater tha 25 mole percent, eachhomolog being present in at least 5 mole percent.

Various secondary amines may be used, both those having the samealiphatic hydrocarbon groups and those having different aliphatichydrocarbon groups. Either alkyl or alkenyl substituents may be presenton the nitrogen, each having at least 14 carbon atoms. The range ofdifference between the two aliphatic hydrocarbon groups bonded at thenitrogen is not critical, but will generally be fewer than 8 carbonatoms, more usually fewer than 6 carbon atoms. For most part, thealiphatic hydrocarbon groups will be straight chain, i.e., normal, withthe amino nitrogen bonded either to internal or to terminal carbonatoms.

It is found that when using approximately a 1:1 mole ratio of amine tosuccinic anhydride, depending on the reaction conditions, a significantamount of amine may be unreacted and remain to form the salt of thesuccinamic acid which is formed. In some instances, as much as 30percent of the amine may remain unreacted, forming a significant amountof salt. Thus, the salt will frequently be from 10 to 30 mole percent ofthe total succinamic acid present.

Also, in situations where significant amounts of water are presentduring the course of the reaction, the water may react with a succinicanhydride to form succinic acid. If the temperature is not high enoughto regenerate the succinic anhydride, the succinic acid will probablyremain unreacted or form the amine salt with available unreacted amine.Therefore, the mixtures of amic acid salts may be conveniently preparedmerely by using a 1:1 mole ratio of amine to succinic anhydride, and notattempting to drive the reaction to completion, or up to a mole excessof amine.

The amine salts are readily prepared by adding the amine to thesuccinamic acid, conveniently as prepared, or in an inert solvent. Mildheating may facilitate the reaction.

The fuel compositions of the invention will comprise a major amount ofthe petroleum distillate fuel, and about 0.005 to 3 wt. percent,preferably 0.01 to 1.0 wt. percent of the additive combination of theinvention. The additive combination, in turn. will comprise about 0.3 to10, preferably 0.5 to 5 parts by weight of Component (A), i.e. the alkylaromatic per part by weight of (omponent (8) and/or Component (C).Component (B) is the ethylene polymer and Component (C) is thesuccinamic acid material. Concentrates of the aforesaid additivecombination can also be prepared containing 3 to 60 wt. percent of thecombination in a mineral oil, e.g., a distillate fuel.

The additive combination of the invention may be used alone as the soleoil additive, or in combination with other oil additives such ascorrosion inhibitors; antioxidants; sludge inhibitors; etc.

The invention will be further understood by reference to the followingexamples which include preferred embodiments of the invention.

In carrying out the Examples, the following materials were used:

Additive A This was a concentrate of about 50 wt. percent of a lightmineral oil and about 50 wt. percent of a wax-naphthalene made from 100parts by weight of n-paraffin wax having a melting point of about 163F.chlorinated to about 12 wt. percent chlorine and condensed with about8.8 parts naphthalene (Friedel-Crafts).

Additive B This was a concentrate of about 50 wt. percent light mineraloil and about 50 wt. percent of wax-naphthalene made by Friedel-Craftscondensation of about 100 parts by weight of n-paraffin wax having amelting point of about l25l29F. chlorinated to about 14.5 wt. percentchlorine based on the weight of chlorinated wax, and about 12 parts byweight of naphthalene.

Additive C This consisted of about 55 wt. percent light mineral oil andabout 45 wt. percent of an ethylene-vinyl acetate random copolymerhaving a number average molecular weight of about 1900 as determined byVapor Pressure Osmometry, having about 1.5 methyl terminated branches(exclusive of the methyl groups in the vinyl acetate) per 1,000molecular weight of polymer and about 38 wt. percent vinyl acetate. Thecopolymer was prepared by copolymerizing ethylene and vinyl acetate withdilauroyl peroxide at a temperature of about 105C., under about 1050psig ethylene pressure in cyclohexane solvent. A typical laboratorypreparation of this polymer is as follows:

A three liter stirred autoclave is charged with about 1000 ml. ofcyclohexane as solvent and about 100 ml. of vinyl acetate. The autoclaveis then purged with nitrogen and then with ethylene. The autoclave isthen heated to 105C. while ethylene is pressured into the autoclaveuntil the pressure is raised to about 1050 psig. Then, while maintaininga temperature of 105C. and said 1050 psig. pressure, about 160 ml/hourof vinyl acetate and about 80 ml/hour of solution consisting of 9 wt.percent di-lauroyl peroxide dissolved in 91 wt. percent cyclohexane arecontinuously pumped into the autoclave at an even rate. A total of 320ml. of vinyl acetate and l 1 gm. of peroxide are injected into thereactor over a period of about 2 hours. After the last of said peroxideis injected, the batch is maintained at 105C. for an additional 10minutes. Then, the temperature of the reactor contents is lowered toabout 60C., the reactor is depressurized, and the contents aredischarged from the autoclave. The emptied reactor is rinsed with 1liter of warm benzene (about 50C.) which is added to the product. Theproduct is then stripped of the solvent and unreacted monomers on asteam bath overnight by blowing nitrogen through the product.

Further examples of this class of polymers are described in CanadianPat. No. 882.194. Details of measuring the branching on this type ofpolymer are given in Journal of Applied Polymer Science. Vol. 15, pp.l737l742 (1971 Additive D This was a concentrate in mineral oil of about60 wt. percent of chlorinated polyethylene having a number averagemolecular weight of about 5100 and a chlorine content of 21 wt. percent.

Additive E This was a concentrate of about 35 wt. percent mineral oiland about wt. percent of active ingredient which was a mixture of (1) anethyleneisobutyl acrylate random copolymer, having a molecular weight(VPO) of about 2000, and a relative mole ratio of ethylene to isobutylacrylate of about 7 to l, and (2) a succinamic acid prepared accordingto US. Pat. No. 3,544,467 Example 1, which is the reaction product ofamolar amount of a di-hydrogenated tallow amine with a molar amount ofalkenyl succinic anhydride wherein the alkenyl groups are isomerized Cmonoolefins. The weight ratio of said copolymer to said succinamic acidis about 1:4.

Fuel A This was a diesel fuel oil having a cloud point of +6F., a pourpoint of -5F., an AP! gravity at 60F. of 33.9, and ASTM distillation(D-86) of 10 percent at 440F. and percent at 625F.

Fuel B This was a diesel fuel oil having a +10F. cloud point, an APIgravity at 60F. of 30.7, and ASTMD-86 distillation of 10 percent at470F. and 95 percent at 621F.

Flow Test A In this test a 200 ml. sample of oil is cooled at a rate of4F./hr. from 10F. above the cloud point of the oil to either 5 or l0F.at which temperature the oil is allowed to pass under 36 inches of watervacuum through a 270 mesh screen of 1 cm. diameter. The percent of thesample that passes through in 25 seconds is reported.

Flow Test B This flow test was carried out in a similar manner as FlowTest A except that a 30 mesh screen was used.

Examples Various blends of the above-noted Additives were made in saidFuels by simple mixing, followed by testing according to Flow Tests Aand B. The specific blends prepared and their cold flow characteristicsare summarized in the following Tables:

TABLE I Fuel Recovery, Flow Test A Wt. 71 Additive in Fuel A with 270mesh Screen 5F. l0F.

O.2'7( C 0.2% A

0.5% A+().l%C 100 0.25% A+0.l5% D 100 0.271 A 0.06% F. 100 None 0 0TABLE II 7/ Recovery in Flow Test B through 30.mesh screen at As seen byTables I and 11, the combinations of the invention of thewax-naphthalene lube oil pour depressant (A and B), with either theethylene backbone pour depressants (C and D) or the succinamic acid'material (E), were synergistic and' more effective improving the coldflow characteristics of these fuels which were made by distillation atatmospheric pressure (i. e., atmospheric distillate oils) by attainingsmallerwax crystals (as determined by the Flow Tests) than the singlecomponents alone.

What is claimed is:

l. A fuel oil improved in its cold flow characteristics comprising amajor proportion of an atmospheric distillate petroleum fuel oil, and aflow improving combination of: V V

A. wax-aromatic lubricating oil pour point depressant which is theFriedel-Crafts condensation product of wax having a melting point ofabout 100 to 200F. chlorinated to about to 25 wt. percent chlorine andcondensed with an aromatic in a relative weight ratio of about 5 toparts of chlorinated wax per part of said aromatic, and a middledistillate fuel oil pour depressant selected from the group consistingof: I

B. an ethylene backbone pour point depressant of about 500 to 50,000number average molecular weight selected from the group'consistin'g of:

l. branched polyethylene, I f I 2. ethylene polymer chlorinated tocontain about'5 to 35 wt. percent chlorine, I

3. copolymers of 3 to 40 molar proportions of ethylene with a C to Calpha monoolefin, or a monoethylenically unsaturated monoor dialkylester having about 1 to 16 carbon atoms in said alkyl groups, and

C. succinamic acid composition of the formula 12 CH cox wherein R is astraight chain aliphatic hydrocarbon having from 0 to 1 sites ofolefinic unsaturation from 14 to 40 carbon atoms and attached at asecondary carbon atom to the succinyl group; one of X and X is NYY,wherein Y and Y are aliphatic hydrocarbyl groups of from l4 to 28 carbonatoms, the other of X and X is of the formula:

wherein n varies from 0 to 1, Y and Y are hydrogen, aliphatichydrocarbon of from 1 to 30 carbon atoms or oxyaliphatic hydrocarbon offrom 1 to 30 carbon atoms, and may be taken together with the nitrogento whichthey are attached to form a heterocyclic ring of from 5 to 7annular members.

2. A fuel oil accordingto claim 1, wherein said composition contains amajor amount of a diesel fuel oil and said wax aromatic iswax-naphthalene.

3. A fuel oil according to claim 2, wherein said middle distillate fueloil pour depressant is said ethylene backbone pour point depressant, andis a copolymer of ethylene with said unsaturated ester.

4. A fuel oil according to claim 3, wherein said unsaturated ester is avinyl ester of a C to C fatty acid.

5. A fuel oil according to claim 4, wherein said vinyl ester is vinylacetate. 7

6. A fuel oil composition according to claim 2, wherein said middledistillate fuel oil pour depressant is said chlorinated ethylenepolymer.

7. A fuel oil composition according to claim 2, wherein said middledistillate pour point depressant is said succinamic acid composition.

8. An additive blend useful for improving the cold flow characteristicsof petroleum fuel oil comprising a mixture of:

A. wax-aromatic lubricating oil pour point depressant which is theFriedel-Crafts condensation product of wax having a melting point ofabout to 200F. chlorinated to about 5 to 25 wt. percent chlorine andcondensed with an aromatic in a relative weight ratio of about 5 to 15parts of chlorinated wax per part of said aromatic, and a middledistillate fuel oil pour depressant selected from the group consistingof:

B. an ethylene backbone pour point depressant of about 500 to 50,000number average molecular weight selected from the group consisting of:

1. branched polyethylene,

2. ethylene polymer chlorinated to contain about 5 to 35 wt. percentchlorine, I 3. copolymers of 3 to 40 molar proportions of ethylene witha C 't o alpha monoolefin, or a monoethyl enically unsaturated monoordialkyl v esterhaving about 1 to 16 carbon atoms in said alkyl groups,and C. succinamic acid composition of the formula R CH 00x CH2 coxwherein R is a straight chain aliphatic hydrocarbon having from O to 1sites of olefinic unsaturation from 14 to 40 carbon atoms and attachedat a secondary carbon atoms 'to the succinyl group; one of X and X isNYY, wherein Y and Y are aliphatic hydrocarbyl groups of from 14 to 28carbon atoms, the other of X and X is of the formula:

wherein n varies from O to 1, Y and Y are hydrogen, aliphatichydrocarbon of from 1 to 30 carbon atoms or oxyaliphatic hydrocarbon offrom 1 to 30 carbon atoms, and may be taken together with the nitrogento which they are attached to form a heterocyclic ring of from 5 to 7annular members in a relative weight ratio of 0.3 to 10 parts of (A) perpart by weight of (B) and- /or (C).

9. An additive blend according to claim 8 which is an oil concentratecontaining about 3 to 60 wt. percent total of said (A), (B) and/or (C).

10. A fuel oil improved in its cold flow characteristics comprising amajor proportion of an atmospheric distillate petroleum fuel oil, and aflow improving combination of:

A. wax-aromatic lubricating oil pour point depressant which is theFriedel-Crafts condensation product of paraffin wax having a meltingpoint of about 100 to 200F. chlorinated to about 5 to 25 wt. percentchlorine and condensed with an aromatic in a relative weight ratio ofabout 5 to 15 parts of chlorinated wax per part of said aromatic, and amiddle distillate fuel oil pour depressant selected from the groupconsisting of:

B. an ethylene backbone pour point depressant of about 500 to 50,000number average molecular weight selected from the group consisting of:

l. ethylene polymer chlorinated to contain about 5 to 35 wt. percentchlorine, and

2. copolymers of 3 to 40 molar proportions of ethylene with a vinylester of a C to C fatty acid,

C. succinamic acid composition of the formula R ca cox CH2 cox wherein Ris a straight chain aliphatic hydrocarbon of from 14 to 40 carbon atomshaving from to 1 site of olefmic unsaturation and attached at asecondary car bon atom to the succinyl group; one of X and X is NYY,wherein Y and Y are aliphatic hydrocarbyl groups of from 14 to 28 carbonatoms, the other of X and X is of the formula:

wherein n varies from O to I, Y and Y" are hydrogen, aliphatichydrocarbon of from 1 to 30 carbon atoms or oxyaliphatic hydrocarbon offrom 1 to 30 carbon atoms, and may be taken together with the nitrogento which they are attached to form a heterocyclic ring of from 5 to 7annular members, and mixtures of (B) and there being present from 0.3 to10 parts of (A) by weight for each part by weight of (B), (C) ormixtures of (B) and (C).

11. An additive blend useful for improving the cold flow characteristicsof petroleum fuel oil comprising a mixture of:

A. wax-aromatic lubricating oil pour point depressant which is theFriedel-Crafts condensation product of paraffin wax having a meltingpoint of about to 200F. chlorinated to about 5 to 25 wt. percentchlorine and condensed with an aromatic in a relative weight ratio ofabout 5 to 15 parts of chlorinated wax per part of said aromatic, and amiddle distillate fuel oil pour depressant selected from the groupconsisting of:

B. an ethylene backbone pour point depressant of about 500 to 50,000number average molecular weight selected from the group consisting of:

1. ethylene polymer chlorinated to contain about 5 to 35 wt. percentchlorine, and

2. copolymers of 3 to 40 molar proportions of ethylene with a vinylester of a C to C fatty acid,

C. succinamic acid composition of the formula R (3H 00x wherein R is astraight chain aliphatic hydrocarbon of from 14 to 40 carbon atomshaving from 0 to 1 site of olefinic unsaturation and attached at asecondary carbon atom to the succinyl group; one of X and X is NYY,wherein Y and Y are aliphatic hydrocarbyl groups of from 14 to 28 carbonatoms, the other of X and X is of the formula:

1. A FUEL OIL IMPROVED IN ITS COLD FLOW CHARACTERISTICS COMPRISING AMAJOR PROPORTIONS OF AN ATMOSPHERE DISTILLATE PETROLEUM FUEL OIL, AND AFLOW IMPROVING COMBINATION OF: A. WAX-AROMATIC LUBRICATING OIL POURPOINT DEPRESSANT WHICH IS THE FRIEDEL-CRAFTS CONDENSATION PRODUCT OF WAXHAVING A MELTING POINT OF ABOUT 100*C TO 200*F, CHLORINATED TO ABOUT 5TO 25 WT. PERCEN CHLORINE AND CONDENSED WITH AN AROMATIC IN A RELATIVEWEIGHT RATIO OF ABOUT 5 TO 15 PARTS OF CHLORINATED WAX PER PART OF SAIDAROMATIC, AND A MIDDLE DISTILLATE FUEL OIL POUR DEPRESANT SELECTED FROMTHE GROUP CONSISTING OF: B. AN ETHYLENE BACKBONE POUR POINT DEPRESSANTOF ABOUT 500 TO 50,000 NUMBER AVERAGE MOLECULAR WEIGHT SELECTED FROM TEGROUP CONSISTING OF:
 1. BRANCHED POLYETHYLENE,
 2. ETHYLENE POLYMERCHLORINATED TO CONTAIN ABOUT 5 TO 35 WT, PERCENT CHLORINE.
 2. ethylenepolymer chlorinated to contain about 5 to 35 wt. percent chlorine, 2.copolymers of 3 to 40 molar proportions of ethylene with a vinyl esterof a C2 to C5 fatty acid, C. succinamic acid composition of the formula2. copolymers of 3 to 40 molar proportions of ethylene with a vinylester of a C2 to C5 fatty acid, C. succinamic acid composition of theformula
 2. ethylene polymer chlorinated to contain about 5 to 35 wt.percent chlorine,
 2. A fuel oil according to claim 1, wherein saidcomposition contains a major amount of a diesel fuel oil and said waxaromatic is wax-naphthalene.
 3. A fuel oil according to claim 2, whereinsaid middle distillate fuel oil pour depressant is said ethylenebackbone pour point depressant, and is a copolymer of ethylene with saidunsaturated ester.
 3. copolymers of 3 to 40 molar proportions ofethylene with a C3 to C16 alpha monoolefin, or a monoethylenicallyunsaturated mono- or dialkyl ester having about 1 to 16 carbon atoms insaid alkyl groups, and C. succinamic acid composition of the formula 3.copolymers of 3 to 40 molar proportions of ethylene with a C3 to C16alpha monoolefin, or a monoethylenically unsaturated mono- or dialkylester having about 1 to 16 carbon atoms in said alkyl groups, and C.succinamic acid composition of the formula
 3. COPOLYMERS OF 3 TO 40MOLAR PROPORTIONS OF ETHYLENE WITH A C3 TO C16 ALPHA MONOOLEFIN, OR AMONOETHYLENICALLY UNSATURATED MONO- OR DIALKYL ESTER HAVING ABOUT 1 TO16 CARBON ATOMS IN SAID ALKYL GROUPS, AND C. SUCCINAMIC ACID COMPOSITIONOF THE FORMULA
 4. A fuel oil according to claim 3, wherein saidunsaturated ester is a vinyl ester of a C2 to C16 fatty acid.
 5. A fueloil according to claim 4, wherein said vinyl ester is vinyl acetate. 6.A fuel oil composition according to claim 2, wherein said middledistillate fuel oil pour depressant is said chlorinated ethylenepolymer.
 7. A fuel oil composition according to claim 2, wherein saidmiddle distillate pour point depressant is said succinamic acidcomposition.
 8. An additive blend useful for improving the cold flowcharacteristics of petroleum fuel oil comprising a mixture of: A.wax-aromatic lubricating oil pour point depressant which is theFriedel-Crafts condensation product of wax having a melting point ofabout 100* to 200*F. chlorinated to about 5 to 25 wt. percent chlorineand condensed with an aromatic in a relative weight ratio of about 5 to15 parts of chlorinated wax per part of said aromatic, and a middledistillate fuel oil pour depressant selected from the group consistingof: B. an ethylene backbone pour point depressant of about 500 to 50,000number average molecular weight selected from the group consisting of:9. An additive blend according to claim 8 which is an oil concentratecontaining about 3 to 60 wt. percent total of said (A), (B) and/or (C).10. A fuel oil improved in its cold flow characteristics comprising amajor proportion of an atmospheric distillate petroleum fuel oil, and aflow improving combination of: A. wax-aromatic lubricating oil pourpoint depressant which is the Friedel-Crafts condensation product ofparaffin wax having a melting point of about 100* to 200*F. chlorinatedto about 5 to 25 wt. percent chlorine and condensed with an aromatic ina relative weight ratio of about 5 to 15 parts of chlorinated wax perpart of said aromatic, and a middle distillate fuel oil pour depressantselected from the group consisting of: B. an ethylene backbone pourpoint depressant of about 500 to 50,000 number average molecular weightselected from the group consisting of:
 11. An additive blend useful forimproving the cold flow characteristics of petroleum fuel oil comprisinga mixture of: A. wax-aromatic lubricating oil pour point depressantwhich is the Friedel-Crafts condensation product of paraffin wax havinga melting point of about 100* to 200*F. chlorinated to about 5 to 25 wt.percent chlorine and condensed with an aromatic in a relative weightratio of about 5 to 15 parts of chlorinated wax per part of saidaromatic, and a middle distillate fuel oil pour depressant selected fromthe group consisting of: B. an ethylene backbone pour point depressantof about 500 to 50,000 number average molecular weight selected from thegroup consisting of: